i realise these problems have come up before as i have searched the forum for them but have yet to find a thread with a solution. i am having alot of problems with my 91 t2 - erratic idle, sometimes nearly dies when stopping, misfiring at idle and all my lights dim (dash/interior lights and exterior lights). the dimming problem seems to be related to the engine speed, ie - if i increase the engine speed the dimming also increases in speed, ocasionally the idle gets perfect and the lights don't dim but only for a few seconds. i have installed an aftermarket volt meter and it reads approx 15.5 with the engine on but this also seems to be linked to the dimming, is 15.5 too high ? i think it still has the stock cats on too. my turbo also occasionally makes a nasty clicking sort of noise at high boost pressures (i,m running approx 9.5 psi). all that may sound pretty bad but otherwise it starts first time everytime and pulls strong. these problems are really beginning to **** me off so any help or suggestions would be greatly appreciated. thanks in advance.

 

15.5 volts is absolute maximum that the system can handle. At 16 volts electronics will start failing.

Sounds like you have a bad regulator or a couple of burnt rectifier/diodes in the alt.

 

15.5 volts is too high,You may have a bad regulator in your alternator.Try replacing your alternator because something is definately wrong with it.Don't forget to check your grounds.A loose ground can cause weird problems with your electrical system.

Good Luck
Danny

 

thanks for the replys, will get the alt checked straight away. i've only had the car a few months but the first thing i did was replace the grounds so i don't think the problem lies there.